Device for operating sliding doors

ABSTRACT

An operator for opening and closing track suspended sliding doors in which motor means, acting on a parallelogram linkage (or pantograph) cause an initial upward and subsequent horizontal movement of the door during opening movement thereof. The upper articulation of the pantograph is mounted for pivotal movement above the track and door and the bottom articulation is pivotally secured to the top of the door.

United States Patent [151 3,673,736

Marchiorello 1 July 4, 1972 [54] DEVICE FOR OPERATING SLIDING [56] References Cited UNlTED STATES PATENTS [721 Marchimm, 484 157 lO/l892 Lawrence 49/235 x I73] Assignec: lnpat Establishment, Vaduz, Liechtenstein 540,262 6/1925 Gmlld "49/234 4 l,935,882 [1933 LC Built! ..49/235 Fllvdl 2,70Ll35 2/1955 llalestrieri... v...A)/3(i3 2H Applv Nu: 81,03 2,755,080 7/]956 Huner ..49/23l Primary Examiner-J, Karl Bell [30] Foreign Application Priority Data Crowe" & weaver Oct. 17, 1969 Italy ..l5589/69 [57] ABSTRACT An operator for opening and closing track suspended sliding [52] US. Cl ..49/235, 49/363 doors in which motor means, acting on a parallelogram link 15/56, E05f15/06 age (or pantograph) cause an initial upward and subsequent Fldd of Search horizontal movement of the door during opening movement thereof. The upper articulation ofvthe pantograph is mounted for pivotal movement above the track and door and the bottom articulation is pivotally secured to the top of the door.

9 Claims, 6 Drawing Figures PATENTEnJuL "4 2972 3.673 736 sum 2 or a Z 4 \l/ g r Fig.4

INVENTOR. G/OVAN/V/ MARCH/ORELLO ATTORNEYS PATENTEDJUL 4 m2 SHEET 3 BF 3 INVENTOR.

GIOVANNI MA RCH/ORELLO A TTORNE KS DEVICE FOR OPERATING SLIDING DOORS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to sliding doors for use in connection with refrigerators and cold storage areas wherein the weight of the door is caused to bear against the sealing members for move effective sealing, and more particularly to an operator for doors of this type wherein, upon opening movement of the door, an initial upward or vertical lift is exerted on the door after which the operator moves the door in a horizontal direction.

2. Description of the Prior Art The present invention relates to a device for opening and closing horizontally sliding doors of the type suspended from a track and requiring an initial upward movement in opening, and is particularly designed for use on doors for refrigerators and other cold storage areas. It is already known to use the weight of a sliding door to obtain an air-tight seal when the door is shut. This is achieved by having a dip in the track from which the door is suspended, the said dip being situated at a point which corresponds with the closed position of the door, so that when the door reaches this closed position, it drops by an amount equivalent at most to the depth of the clip. The airtight seal around the edge of the door is obtained not only by means of the weight of the door itself but also by means of the pressure exerted on the seals placed round the circumference of the door.

In order to open a door of the type described above, the door must be moved horizontally with a simultaneous upward movement during the initial phase. While it is commonly known to use a cylinder/piston system pivotally connected to a door and'secured to a fixed external point in order to obtain the horizontal movement (see for instance, U. S. Pat. No. 1,657,554, issued Jan. 31, 1928), such mechanisms do not resolve the problem of the vertical component that is required in the initial movement. Furthermore, in the cases where means are provided to obtain the vertical movement, a disadvantage arises from the fact that a powerful motor is needed to lift the dead weight of the door, whereas relatively little power is needed to obtain the horizontal displacement of the door. The motor has therefore to be larger than is required for much of the work, which is both technically and economically unsound.

SUMMARY OF THE INVENTION The present invention is designed to overcome the abovementioned disadvantages by means of an operating device consisting of a parallelogram linkage or pantograph having the upper ends of its upper arms or links pivoted or articulated on a fixed point above the sliding door, the lower ends of its lower arms or links pivoted or articulated on a bracket attached to the door, and the lower ends of the upper links being pivotally connected or articulated with the upper ends of the lower links. The last connections are free to move in a lateral direction. A mechanical source of power is pivotally attached to the upper links in a plane parallel to the diagonal extending between the free or unattached articulations of the pantograph, whereby the free articulations may be moved toward or away from each other, and will impart an initial vertical component of force, followed by a horizontal component of force for opening of the door. Also according to the present invention, the upper articulation is situated at a point equidistant from the ends of the travel of the lower articulation.

The lower articulation may be attached to the upper edge of the door or placed in any other suitable position above this edge.

It is a primary object of the invention to provide a door operator that is capable of moving a sliding door initially in a vertical direction and subsequently in a horizontal direction.

It is a further object of the invention to provide an operator of this type for use in combination with a sliding door and a track having dips or cam surfaces whereby the weight of the door will be exerted against the sealing strips to effect better sealing.

Yet another object of the invention is to provide a sliding door operator that is simple, inexpensive to manufacture and which will operate efiiciently.

Other objects and advantages of the instant invention will become more manifest from a consideration of the following specification when read in the light of the annexed drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view of the operating device of this invention attached to a track suspended sliding door with the door in closed position;

FIG. 2 is a view similar to FIG. 1, but showing the door in a partially opened position;

FIG. 3 is a sectional view taken on the lines III-III of FIG.

FIG. 4 is a perspective view, partially broken away and partially in section, of the operating device attached to the door, with the door in a partially opened position, and showing a masking wall;

FIG. 5 is a perspective view, partially broken away, of the operating device and including a retarding device; and

FIG. 6 is a perspective view of a modified form of the operating device.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more specifically to the drawing, a door 1 is provided for a refrigerator cold storage area or other type storage area. The door is provided with integral inwardly extending sealing flanges 1' and is suspended from an overhead track 2. Brackets 4' are mounted on the top edge of the door and rollers 4 are joumalled on the brackets to support the door for rolling movement on track 2. The track 2 has a spaced pair of dips or depressions 3 adjacent the end of the track to permit the door 1 to drop downwardly when it is in closed position.

The refrigerator or storage area has a wall 5 in which a doorway or opening 5 is provided and a masking wall 6. The door 1 slides between the wall 5 and the masking wall 6 and will be hidden by the masking wall when the door is open as in FIG. 3. Sealing flanges 5" are provided on the top and sides of the door frame.

Where the door is being used on a refrigerator or cold storage area the door is provided with air-tight seals 7. When the door is moved to closed position the rollers 4 will fall in dips 3 in the track 2 and the weight of the door will compress the seals 7 against the sealing flanges 5" and the floor.

A centrally disposed bracket 8 is attached to the top edge of the door 1 intermediate of the roller brackets 4'. The numeral 9 refers generally to a parallelogram linkage, hereinafter referred to as a pantograph. The pantograph has a pair of upper arms or links 9' and a pair of lower arms or links 9", with the links being pivotally connected or articulated, as at l0, l0, l7 and 17. The upper articulation 10 is securely attached to wall 5 as by a support rod 10" and serves as a fixed point on which pantograph 9 pivots. The lower articulation 10' is pivotally attached to bracket 8. Articulations l7 and 17' are not secured and are free to move in both horizontal and vertical planes.

A mechanical source of power, such as fluid motor 11, is provided and includes a piston 12 slidably mounted in a cylinder 13, a spring 14 and a supply line 15 connected to a source of fluid supply (not shown) and having control means (not shown) for controlling admission of fluid to the cylinder. The free end of the piston rod is pivotally attached to one of the upper arms and the cylinder 13 is pivotally attached to the other of the upper arms, as is best shown in FIG. 4, whereby the force of the fluid motor will be exerted in a plane parallel to the diagonal line between the free articulations 17 and 17 The spring 14 is biased to normally bring the free articulations 17 and 17' together (as shown in FIG. 1). When fluid is introduced into the cylinder 13 through supply line 15, the force of spring 14 is counteracted by the pressure of the fluid on the piston 12 to force the free articulations l7 and 17 apart as shown in FIG. 2. A damper 16 is also provided, the opposite ends of which are pivotally connected to the lower arms 9", for the purpose of dampening the movement of the free articu lations during the horizontal component of their movement. The damper is preferably disposed for operation in a plane parallel to the piston and cylinder.

instead of the spring 14, a dynamic fluid system or an electromotive system, acting in a similar fashion may be used. Likewise, in place of the dynamic fluid system comprising the piston 12, the cylinder l3 and the fluid introduced through line 15, a mechanical or electrical system could be used. Further, instead of a pantograph having four arms, a device having a greater number of arms could be used, as for example, six arms (9'9', 9"9" and 9' "-9"') as is shown in F IG. 6. This arrangement would make it pmsible to reduce the space occupied by the pantograph itself.

In operation, when the door is shut the free articulations l7 and 17 will be at their closest point and the upper and lower articulations l and 10 will be at their farthest point of separation. The rollers 4 will be in the dips 3, and, due to gravity, the door 1 will be compressing the seals 7. Spring 14 will be extended to its maximum position.

In order to open the door 1, fluid is introduced into cylinder 13, causing piston 12 to be moved against the force of spring 14, and thereby causing the angle between the upper arms 9' and 9' and the angle between the lower arms 9" and 9" to be increased. This movement causes a shortening of the distance between the upper articulation l0 and the lower articulation 10'. The pantograph 9 will act like a series of levers, and, during the initial phase, the force exerted on the lower articulation l0"will be greater than that exerted by the piston. The force applied at the lower articulation 10 will be at an angle to the track so that there will be a vertical component which will lift the rollers 4 out of the dips 3, and a horizontal component,

which will move the door horizontally at a rapidly increasing rate of speed.

During the first stage-of the horizontal movement of the door, and up to the point when the lower articulation 10 reaches a point immediately below the upper articulation 10, the spring 14 is storing energy. Once this position, which corresponds to the half-way point of the door's travel, is reached, the door continues to move under its own impetus, aided by the energy stored in spring 14, until it reaches its fully open position between the walls and 6. At the same time, the fluid in the cylinder 13 will be released through line 15. During the latter phase of the doors movement the damper 16 is operative to prevent slamming of the door and to insure that there are no abrupt changes in speed.

Once the door is fully open, it can be closed again be reintroducing fluid into the cylinder 13 so that the same sequence of events is followed as for opening the door.

As will be seen, the presence of the spring 14 ensures that there are only two stable positions for the door 1 which are open and shut. All other positions will be unstable. The two positions correspond to the same position of maximum separation of the upper and lower articulations of the pantograph.

Having described and illustrated the invention in detail, the

a pantograph having a pair of upper arms and a pair of lower amts pivotally connected together to form an upper articulation, a lower articulation and a pair of opposed free articulations,

fixed support means disposed above said track, said upper articulation being pivotally secured to said support 0 0 means pivotally securing said lower articulation to the upper part of said door at a point below said support means, power means acting on said pantograph in a direcuon parallel to a diagonal between said free articulations for causing movement of said free articulations away from each other to effect opening or closing movement of said door, and biasing means acting on said pantograph for bringing said free articulations back to a position of proximity in the fully opened and fully closed positions of the door. 2. A device as set forth in claim 1 in which the fixed support 2 5 means, upon which the upper articulation is pivotally secured, is located at a point equidistant from the ends of the travel of the lower articulation.

3. A device as set forth in claim 1 whereinthe means pivotally securing the lower articulation to the door consists of 30 a support bracket mounted on the top edge of the door.

4. A device as set forth in claim 1 wherein the means pivotally securing the lower'articulation to the door consists of a support bracket mounted on the'door below the upper edge thereof.

5. A device as set forth in claim 1 wherein the power means includes a cylinder that is pivotally secured to one of said upper arms,

a piston and piston rod mounted for reciprocation in said cylinder, the free end of said piston rod extending out of said cylinder and being pivotally secured to the other end of said upper arms,

a source of fluid for operating said piston,

a supply line connecting said fluid source and said cylinder,

and

means for controlling the flow of fluid from said fluid source to said cylinder.

6. A device as set forth in claim 1 wherein said biasing means comprises a spring disposed between said upper arms of said pantograph.

7. A device as set forth in claim 5 wherein said biasing means comprises a spring disposed in said cylinder, said spring normally biasing said piston to a position where the free articulations of said pantograph are in close proximity.

8. A device as set forth in claim 1, including damper means 55 secured to said pantograph for retarding movement of said door after it has passed its midpoint of travel.

9. A device as set forth in claim 7 wherein damper means extend between and are pivotally secured to said lower anns of said pantograph for preventing too rapid movement of the 6() door.

UNITED STATES PATENTGFFICE flERTIFlQATE 0F CRECTKN Patent No. 3,673,736 Dated uly 7 lnventofls) Giovanni Marchiorello It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The foreign application upon which priority is based is hereby changed to show that such priority claim was based on Switzerland Patent Application No. 15589/69, rather than upon an Italian application.

Signed and sealed this 30th day of January 1973.,

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. An operator for opening and closing a horizontally sliding door of the type suspended from a track and requiring an initial upward movement for opening, including: a pantograph having a pair of upper arms and a pair of lower arms pivotally connected together to form an upper articulation, a lower articulation and a pair of opposed free articulations, fixed support means disposed above said track, said upper articulation being pivotally secured to said support means, means pivotally securing said lower articulation to the upper part of said door at a point below said support means, power means acting on said pantograph in a direction parallel to a diagonal between said free articulations for causing movement of said free articulations away from each other to effect opening or closing movement of said door, and biasing means acting on said pantograph for bringing said free articulations back to a position of proximity in the fully opened and fully closed positions of the door.
 2. A device as set forth in claim 1 in which the fixed support means, upon which the upper articulation is pivotally secured, is located at a point equidistant from the ends of the travel of the lower articulation.
 3. A device as set forth in claim 1 wherein the means pivotally securing the lower articulation to the door consists of a support bracket mounted on the top edge of the door.
 4. A device as set forth in claim 1 wherein the means pivotally securing the lower articulation to the door consists of a support bracket mounted on the door below the upper edge thereof.
 5. A device as set forth in claim 1 wherein the power means includes a cylinder that is pivotally secured to one of said upper arms, a piston and piston rod mounted for reciprocation in said cylinder, the free end of said piston rod extending out of said cylinder and being pivotally secured to the other end of said upper arms, a source of fluid for operating said piston, a supply line connecting said fluid source and said cylinder, and means for controlling the flow of fluid from said fluid source to said cylinder.
 6. A device as set forth in claim 1 wherein said biasing means comprises a spring disposed between said upper arms of said pantograph.
 7. A device as set forth in claim 5 wherein said biasing means comprises a spring disposed in said cylinder, said spring normally biasing said piston to a position where the free articulations of said pantograph are in close proximity.
 8. A device as set forth in claim 1, including damper means secured to said pantograph for retarding movement of said door after it has passed its midpoint of travel.
 9. A device as set forth in claim 7 wherein damper means extend between and are pivotally secured to said lower arms of said pantograph for preventing too rapid movement of the door. 